Exposure of cattle in Michigan to PBB via contaminated grain resulted in subsequent exposure of farm families to these toxins. A study of children exposed to PBB indicated they may show subtle disturbances in learning patterns, but conclusive evidence of perinatal toxicological influences in humans appears to be lacking. A recent study demonstrated perinatal toxicology in rats to fairly large doses of PBBs. The present study examines the potential of lower levels of PBB administered to rats perinatally to induce lasting changes in behavior. Groups of gravid females will receive various dose levels of PBB in their diet: 0, 0.06, 0.6, or 6.0 mg/kg/day. The largest dose, equivalent to 100 ppm, affects behavior in the adult rat. Four conditions will be imposed, administration of the toxin: 1) during gestation, 2) during gestation and lactation, 3) during lactation only, and 4) administration of vehicle only. All pups will be cross-fostered, and half will be examined in open field behavior prior to weaning and then be sacrificed at weaning for determination of plasma and brain levels of PBB. The remainder will be raised to 60 days of age, then examined for accommodated locomotor activity and tested for d-amphetamine stimulation of this behavior. Following this, a portion of the subjects will be trained to a conflict procedure. When stable, these subjects will be tested for effects of d-amphetamine to enhance punishment suppression and of diazepam to increase punished responding. The other portion of the animals will be trained to a multiple operant schedule (Fixed Ratio, Fixed Interval) of food reward. When stable, these subjects will be tested for the effects of d-amphetamine and chloral hydrate. Most of the offspring will be sacrificed at 4-8 months of age to measure plasma and brain PBB. However, when a dose level of PBB does not alter behavior in the multiple operant schedule, these subjects, along with controls, will be maintained to 18 months of age and retested. They will then be sacrificed for determination of plasma and brain PBBs. Based on prior studies, at least one dose level should affect behavior. We will attempt to define the lowest dose level of PBB exposure which affects the behavioral patterns, and/or drug actions thereon, as an index of potential neurobehavioral toxicity in humans exposed perinatally.